It is desired to test the operation and performance of a camera at temperatures other than ambient, e.g. cold temperatures such as −40° C. Cold testing is typically done inside an environmental test-chamber. However, the targets used to determine the operation and performance of a camera may be too large to fit inside an economically priced test-chamber. It has been suggested to place the target outside of the test-chamber and have the camera view the target through the multi-pane viewing-window that is typically provided with a test-chamber. The viewing-window is a multi-pane configuration to prevent fogging/frosting of the viewing window during cold testing. However, the multi-pane configuration causes an unacceptable amount of image distortion for camera testing.